Transmission gear of motor road vehicles



Mal'. 6, 1923.

E. I. nEiNoRMANv'ILLE. TRANSMISSION GEAR 0F MOTOR ROAD VEHICLES.

FILED AUG-I2 |920.

//I Mr l which brake drums when Patented Mar. 6, 1923.

raiser raies EDGAR JOSEPH DE NORIVIANVIILLE, OF LON DON, ENGLAND.

TRANSMISSION' GEAR OF MOTOR ROADVEHICLm.

Application led August 12, 1920. Serial No. 403,067.

To allwhomz'tmay concern.'

Be it known that I, EDGAR JOSEPH DE NORMANVILLE, a subject of'the Kingof Great Britain, residing at London, England, have invented new anduseful Improvements relating to Transmission Gears of Motor RoadVehicles, of which the following is a specification.

This invention relates tothe transmission gear of motor road vehiclesand particularly to vehicles provided with epicyclic gears of the brakecontrolled type, and the said invention provides a novel form of brakeapparatus for changing the speeds and a novel method of controlling theapplication and release of the brakes.

According to my invention, the several brake drums are provided withbrake bands in the preferred form are wound spif rally round the drumsand embrace more than one complete turn, 'one end of each Ibrake bandbeing'anchored, and the free end being connected, preferably through aspring, to the means for applying the brake.

etracting springs are t provided to release the brake bands and drawthem clear of the the actuating means are inoperative. The direction ofwinding of each brake band is such that frictional contact of the bandand drum tends to apply the brake. c

Brake bands thus constructed can be put into operation with a minimumeffort.

I prefer to apply thebrakes initially to start the braking action byelectro-magnetic means controlled by a small lever on the steering wheelor column for making and breaking the electric circuits, but if desiredthe brake band may be moved to the operative position by mechanicalmeans, the arrangement being suclr'that when once moved to the operativeposition the brake band will be maintained in this position withoutfurther or continued effort on the part of the operator. Y

In the accompanying drawing Figure l is a side view of a portion of avariable speed transmission gear having this invention applied thereto,with' parts in section. f

.Figure 2f/is anend view showing one of the brake drums and theappurtenant brake band and band operating devices.

As shown in this drawing, brake drums a, aare provided with brake bandb, b', respectively, each of which is lapped more than v positionagainst the brakes,

one comglete turn round the corresponding drum. ne end of each band issecured -to the casing as at c and the opposite end of the band isconnected through a spring d to one arm of a bell crank lever e pivotedat 'j'. By moving the lever e to the position indicated in broken linesin Figure 2 the band b is brought into frictional contact with the drum@and can be maintained in'this operative position by a very small forceowing to the manner in which the band is mounted with reference to thedirection of rotation of the drum, so that the grip of the band on thedrum is maintained or increased as soon as these parts are .brought intosufficient frictional contact.

retracting spring g is provided to release the band b and draw it clearof the drum a when the lever e isreturned to the position shown in fulllines in Figure 2.

If preferred the springs al and g may be arranged to operate incompression instead of in tension. A

The lwhole of the variablevelocity ratio gear including the brake drumsand bands is enclosed in a casing L containing oil so that the surfacesare continuously lubricated and further the gear casing is preferablybuilt up as part ofthe engine casing.

The lever e can be, conveniently moved by an arm i pivoted to an arm y'which. in turn is mounted on a fixed pivotk, the arms z',

j forming a toggle for which purpose they are arranged so that the jointconnecting them together is carried a little below the line of alignmentof these arms when the lever e isin the position shown in broken lines.The lever e is thereby held in this pull of the spring g.

With this arrangement the brake is applied by movement of a memberconnected to the arms z'.,- j, at the connecting joint. Each brake band\in the gear is operated separately by a similar device correspondingthereto.

In the arrangement shown in Figure 2, the arms i, ,7' are moved byianelectro-magnet Z energized by a circuit including a control arm mmovable in a gate plate n. This arm when brought to the end of any oneof the channels in the plate n closes a corresponding circuitorici-rcuits including the electromagnet or electromagnets of one or vdevices so that any of the as'required to give different velocity can beapplied by exerting only 'so more of the brake ratios,

. of the eleetromagnet and to release the arms l5 much effort as isrequired to operate the switch arm m, and when applied will bemaintained in operation by the arms z', j. A switch vo operated by apedal p is provided to control all'the circuits so that by depressingthis pedal all the circuits are broken to liberate the brakesirrespectively of which of them is in operation at the time. For thispurpose the circuits through all the electromagnets of which only one isshown in the drawing, are brought to one pole of this switch.

A spring g is provided to raise the core 1' z', 7' from their lockedposition.

The control of the brake is effected by minimum expenditure of electriccurrent, the operative position of the brake being ensured by the'togglearms or cam. Also for the same reason. Iwhen theelectrical control isomitted and the toggle arms or their equivalent are moved directly or bymechanical connection to a hand lever, the usual devicesfor locking thelsaid lever in yitsvgate glate can be dispensed with.

hat

claim is 1. Brake mechanism comprising a brake drum, a brake band aroundthe drum, a Xed anchorage for one end of the band, a pivoted brakeoperating member, a spring connecting the otherA end of the banditothesaid operating member, an electromagnetically operated device formoving the operating member to and locking same in a position to holdthe brake band operative,

and means for lunlocking the operating Amember and moving same torelease the ating member connected to the said band,

arms pivoted together toform a toggle, one

arm being pivoted to a fixed support and the other arm being pivoted tothe brake operating member, an electromagnet operating through thepivotal joint between the said arms to movethe operating member and holdthe brake band in its operative position, and a spring acting on thesaid pivotal joint to release the toggle and brake band.

3. Brake mechanism comprising a brake drum, a brake band Wound spirallymore than one completellap around thel drum, a fired anchorage for theleading end of the said band with respect to the direction of rotationof the drum, a pivoted brake operating member connected to the other endof the brake band, an electromagnetically operated device for moving theoperating member to and locking the same in a posif 'tlon/ to holdA thebrake band operative, and

means for unlocking the operating member and moving the same to releasethe brake band from the drum.

EDGAR JOSEPH de NORMANVILLE.

